Playing sound in main movie

Hello,
There,

I made cd presentation. My prob. is that to play sound from main file.
Let me describe …

for cd presentaion i made main movie say “cddemo”
i required links into like home,about,products etc…so i made seperate files say
home.swf,about.swf, products.swf…etc

and that files will loaded in to main movie say “cddemo” by action loadmovieNum();

then i put sound on button in the respective movie say home.swf, about etc…
when i test that movie seperately…sound is paly perfectly when i click the buttons

but main prob. is that when i test this file through main movie…“cddemo”…sound on the button does’t play what’s the prob…

pls tell me!